Have you ever been on drugs and looked down at where your dick is supposed to be and thought … where the fuck is my penis?

A focusing of the eyes reveals that it's mercifully still there, but there appears to be something very wrong with it. It's sick.

Shriveled and bunched up like an unfriendly turtle, it's fully recoiled to its tiniest possible proportions, naked and afraid. Sex seemed like great fun a few minutes ago, but now, no way is it happening.

Welcome to the regrettable, yet common phenomenon of male drug shrinkage. A flaccid and unresponsive phallice is one of the classic hallmarks of drug use, but the question remains: Which substances are the the worst for this, and why?

Well, in short (pun intended), it all has to do with how a drug affects your cardiovascular system.

"If you think of erectile physiology, you need blood flow, so anything that restricts blood flow is a bad thing," said John P. Mulhall, the director of the Male Sexual and Reproductive Medicine Program at Memorial Sloan Kettering Center to VICE. "Like adrenaline: It's a tremendous blood-flow restrictor, so anything that would function similarly to adrenaline — MDMA, for instance — could be extremely bad for your erectile function."

MDMA/ Ecstasy

Ah, the inimitable paradox that is sex on MDMA.

While MDMA releases a tsunami of serotonin that alters your personality and turns you into a cuddling, fawning lust-mess, that exact same serotonin also works as a vasoconstrictor, narrowing the blood vessels in your bod all the way down to your penis.

This creates the baffling, opposing sensations of feeling extremely horny and sensual, while not being able to achieve the erection to prove it.

That, or you can get it up and fuck for 13 hours because the serotonin has diverted blood away from the reproductive glands that make you ejaculate. Great if you're setting a record, awful if the person you're fucking isn't made of silicone.

You also might have noticed that you can't pee while you're on MDMA, even though you feel like you have to. That has nothing to do with your penis' blood flow, but with MDMA causing the release of the hormone vasopressin, which controls the kidneys' retention of water.


Being one of the most potent stimulants your nose will ever know, cocaine will also make you horny but prevent you from doing anything about it for the same vasoconstrictor-y reasons MDMA does.

In fact, this effect is so certain that researchers seem to think that the perceived increase in arousal and pleasure people report on cocaine is actually false.

"I think when you speak to people about cocaine, they'll often say [sex] is way better," said Mulhall to VICE. This would appear to corroborate a 2002 study that found 40 to 50 percent of respondents experienced an increase in sex drive, fantasies, pleasure, performance, obsession, and unusual or risky sexual behaviors while using coke. "But it's really a perceptual issue. I don't think there's anything to be gained — from an erectile function standpoint — in any of these agents [drugs] in the short or long-term."


Let's see a show of hands. Who here has had whiskey dick?

All of you?

That's what we thought. Well, Mulhall has an explanation for that:

"It's a social lubricant, so there's increased levels of relaxation, but every person is going to have a different threshold dose, beyond which it's going to suppress the central action of the brain," said Mulhall. "It's a central depressant, so it's going to have a negative effect at a certain dose on the brain centers that trigger erections. They're like the sparks that get everything going. You need them."

Long story short? If you're trying to fuck, or fuck yourself, just drink a little bit. Keep yourself below your threshold dose of booze, and you should be able to hump professionally all the live long day.


At small doses, a small bump of ketamine enhances brain function and increases libido, according to Tim Williams, the clinical director at Bristol Specialist Drugs and Alcohol Service.

Any more than that, however, and the dissociative nature of the drug can mean sex is the last thing you want to do.

Also, you guys, ketamine is a horse tranquilizer. If it can knock out a stallion, it can sure as shit knock out your dick. It's an numbing anesthetic that makes it very hard to feel things, and this can send your erection running and screaming from the bedroom. 

It does relax muscles though, so … fisting is always an option when your dick goes AWOL.


This one's tough because what effect the weed has on your cock is entirely dependent on what strain it is.

Some strains act as vasodilators, while others act as vasoconstrictors. Even more confusingly, these effects are reversed in some people, depending on their individual biochemistry and experience with weed.

As for weed's relationship to libido, researchers are divided. There are many contradictory reports about what THC does to your dick, and what scientists have found often seems at odds with the reported experience of users.

Typically, the common thread in research communities seems to be that marijuana make you horny on its own, but it does affect certain sexual organs in a way that boosts sex drive in some people (but not others).

For example, some women in the study notice increased vaginal lubrication, but other reports from women on weed say the opposite; that it dries them out.

One University of Kansas study found that while weed didn't increase the number of orgasms people had, or increase sexual frequency, it did appear to have an "aphrodisiac-like" quality, as earlier studies cited.

"Over two-thirds reported increased sexual pleasure and satisfaction with marijuana," the study's lead author wrote. "Increased desire for a familiar sexual partner was reported by about one-half. The sensations of touch and taste were particularly enhanced by marijuana. Many felt marijuana was an aphrodisiac."

You really just have no way of knowing what it'll do to your wang until you try it, but that's fine and dandy because it's the safest thing you could experiment with. Great!

And as for what substances do the opposite of these, and make your dick all juicy and enormous?

Well, there's Viagra if you like a good old fashioned, excruciating 12-hour erection, or … you can just get high on life.

Not what any of us wanted to hear, but … a sober erection is better than a tiny k-hole penis anyday.